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I have 2 older 18V pedals. A Roland AP2 big box phaser and a Univox M1000 Effectomatic (mutron copy) that are in need of repair.When I opened them to change the batteries they just stopped working. They both worked fine, now they don't.

The last sound the Roland gave off was a short high pitched degrading squeal when i was moving the batteries around to close the box (no screws).The Univox worked and now it just doesn't. So upsetting. I don't think it's a loose solder joint because I definitely poked around but who knows?Input jack gives no noise when plugging in, but I get a crackle sound from the amp when plugging in the output jack. I also cleaned the footswitch with deoxit and compressed air to no avail.

Though I was careful handling them, they were just so fragile I guess. Any help on fixing either would be much appreciated. The Univox is the one I would like to fix soon because its not mine and was in for a simple switch repair.

perhaps some old caps gave up and died old gear can break in so many waysI guess you will need to do some troubleshooting, see if you can get the schematics, test the supply rails, probe the audio path etc